With rapid development of science and technology, the requirement on sounding devices is increasingly higher, and the performance of the diaphragm, which is a kernel component of the sounding device, directly influences the performance of the sounding device.
An important factor to evaluate the performance of the diaphragm is natural frequency. In prior art, a natural frequency of a diaphragm is acquired in such a way that the diaphragm is located in a unclosed environment, the diaphragm vibrates under the driving of an excitation sound source, and the frequency corresponding to the maximum sound pressure to which the diaphragm is subjected is taken as the natural frequency of the diaphragm.
Several problems exist in the above measurement method:
1) since the natural frequency of the diaphragm is acquired in a unclosed environment, the measurement result tends to be affected by surroundings, which results in a larger error in the measurement result;
2) when the frequency of the vibration of the diaphragm is equal to the natural frequency of the diaphragm, the amplitude of the vibration of the diaphragm is maximized, and because the amplitude of the vibration of the diaphragm may not be maximized when the diaphragm is subjected to the maximum sound pressure, it is not accurate to take the frequency corresponding to the maximum sound pressure to which the diaphragm is subjected as the natural frequency of the diaphragm;
3) the distortion amount generated when the diaphragm vibrates during acquisition of the natural frequency of the diaphragm cannot be acquired.
Consequently, there is a need for a novel technical solution capable of acquiring the natural frequency of the diaphragm.